Check the Facts on Global Warming

[DearAbby]

For those who wish to point to “natural cycles” re warming vs carbon dioxide, I would again like to remind one of the world’s four great glaciations — the Gunz, Mindel, Reiss and Wurm — that roughly coincided with the Milankovich cycles with “tipping points” occurring with the Maunder Minimums and at times, volcanic eruptions.

Based on those cycles, we should be COOLING. Obviously we are not as evidenced by the annual 3mm of sea level rise since 1993. This rise may be most noticed this year at perihelion and the new moon in the middle of January and noted for future reference.

In addition to carbon dioxide, methane and water vapor contribute to the warming. With deforestation, forest fires and pine bark beetles and concomitant decrease in carbon sequestration, the carbon dioxide build-up is proceeding at a rapid pace. Coal-burning power plants here and in China do NOT help.

I would recommend checking www.farnorthscience.com with the various links for some scientific “grounding” in the subject.

http://www.kitsapsun.com/news/2009/nov/26/letter-to-the-editor-check-the-facts-on-global/#comments

This was LTTE submitted by a friend of mine, I wonder what your thoughts are on the subject.

[DearAbby]

1. Milankovitch Theory

Milankovitch Theory describes the collective effects of changes in the Earth's movements upon its climate, named after Serbian civil engineer and mathematician Milutin Milanković. Milanković mathematically theorised that variations in eccentricity, axial tilt, and precession of the Earth's orbit determined climatic patterns on Earth, resulting in 100,000-year ice age cycles of the Quaternary glaciation over the last few million years. The Earth's axis completes one full cycle of precession approximately every 26,000 years. At the same time, the elliptical orbit rotates, more slowly, leading to a 23,000-year cycle between the seasons and the orbit. In addition, the angle between Earth's rotational axis and the normal to the plane of its orbit moves from 22.1 degrees to 24.5 degrees and back again on a 41,000-year cycle. Currently, this angle is 23.44 degrees and is decreasing.

The Milankovitch theory of climate change is not perfectly worked out; in particular, the largest observed response is at the 100,000-year timescale, but the forcing is apparently small at this scale, in regard to the ice ages.<1> The frequency modulation<2> or various feedbacks (from carbon dioxide, cosmic rays or from ice sheet dynamics) explain this discrepancy.

Milankovitch-like theories were advanced by Joseph Adhemar, James Croll and others, but verification was difficult due to the absence of reliably dated evidence and doubts as to exactly which periods were important. Not until the advent of deep-ocean cores and a seminal paper by Hays, Imbrie and Shackleton, "Variations in the Earth's Orbit: Pacemaker of the Ice Ages", in Science, 1976,<3> did the theory attain its present state.

http://en.wikipedia.org/wiki/Milankovich_cycles